1. Field of the Invention
This invention relates to a food dispensing or vending machine, and particularly to a food dispensing machine which dispenses both hot and cold foods. This invention is more specifically directed to a coin-operated vending machine for dispensing food and selectively heating foods stored in a cold storage area prior to delivery to a customer.
2. Brief Description of the Prior Art
Coin-operated machines for dispensing various kinds of food and drink to a prospective customer are well known. It is often desirable to incorporate into a single machine foods which are dispensed either hot or cold, depending upon the choice of the purchaser. In machines which keep food continuously heated, the item of food has often been delivered to the purchaser in a soggy and unpalatable condition. This sogginess is caused by condensation within the sealed glassine or plastic wrapping about the item of food. It has also been the practice in such machines to display the items of hot food through glass windows, so that the prospective purchaser may select the type of food which he desires from visual inspection. Where the item of food has been stored in the dispensing machine for a period of time in a heated condition, it will often appear unappetizing to the customer, thus dissuading the customer from purchasing food from the machine. In machines where the customer is allowed to see the item of food, it is common to have a drum type of storage and delivery unit from which the customer removes the item of food through a door. This type of storage and delivery limits the capacity of the machine or, where greater storage capacity is desired, the machine must be enlarged to gargantuan proportions.
Where it is desired to dispense both hot and cold foods from the same machine, it has been the practice to have two separate storage chambers which must be sufficiently insulated from one another, and which must be separately heated and cooled. This necessitates provision of a separate heating unit and a separate cooling unit, thus increasing the bulk of the machine.
It has been previously proposed to utilize a microwave oven, infrared oven, or other food-heating device in conjunction with a cold-storage food vending machine to provide either hot or cold food, as desired by the purchaser at the time of purchase. One such arrangement is disclosed in U.S. Pat. No. 3,416,429. In that arrangement of a food vending machine, food articles are stored in a plurality of vertically disposed storage racks within a refrigerated chamber in the upper portion of the machine. At least one of the storage racks is situated so as to deliver an article of food to a microwave oven to be heated. After a heating cycle is completed, the heated article of food is delivered to a receptacle bin. Individual selector mechanisms permit the purchaser to select either a heated article, such as, for example, a heated roast beef sandwich, or a cold article, such as, for example, a tuna salad sandwich. The cooking chamber of the microwave oven is perforated, so that water vapor, generated by heating condensation or native moisture in the article, is permitted to escape. As a consequence, even though rapidly heated, the hot food is delivered with an attractive appearance and a palatable texture, and is prevented from becoming soggy.
However, the microwave oven is sensitive to stray moisture. While the above food vending machine includes a trap to prevent condensation within the cold storage compartment and prevent that moisture from dripping into the microwave oven, it does not include any provision to prevent the moisture generated upon heating a food article from condensing and dripping back into the oven. Thus, the vending machine will deliver properly heated food if there is sufficient time for the moisture to dissipate, but may begin to experience difficulties during heavy use periods, such as during lunch and supper periods. At those times, sufficient condensation can accumulate and drip down into the microwave oven to disturb the preset cooking cycle, or can affect some of the electronic circuitry.